Every winter we have a period of time where we spray almost the entire course with herbicides. What we are trying to achieve with this practice is the removal of all unwanted grass species, weeds. The definition of a weed is, any grass that is not desired in a certain area. In our case we want 419 Bermudagrass and Meyer Zoysiagrass as our two higher cut grasses. In order to maintain the two main types of desirable grasses we have to apply pre emergent and post emergent herbicides. Typically a stand of turf should have a pre emergent herbicide applied in the Spring and the Fall. Each one of these applications should last about 6 months. They prevent any new seeds from germinating in the soil. Unfortunately we only apply one pre emerge application per year. We couple this with a "Round Up" application in the dead of winter when the Bermuda and Zoysia are completely dormant. This way we can kill any weeds in the Bermuda and Zoysia without harming the desired turf. This year we are focusing on removing any of the existing over seeding from last year that may still be hanging around. I have a few pictures below to illustrate the timeline of damage.
This is the Chipping Area. It has not been sprayed with "Round Up" at this time. You can see the Ryegrass is nice and green.
This is the right edge of the Putting Green Collar. If you look carefully you can see the defined line in the middle of the picture where the "Round Up" has been sprayed 27 days ago. The right side of the line is Bentgrass in the collar that is starting to yellow out.